6533b834fe1ef96bd129cb1c

RESEARCH PRODUCT

Kinetics and Intensity of the Expression of Genes Involved in the Stress Response Tightly Induced by Phenolic Acids in <i>Lactobacillus plantarum</i>

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description

In <i>Lactobacillus plantarum</i>, PadR, the negative transcriptional regulator of <i>padA </i>encoding the phenolic acid decarboxylase, is divergently oriented from <i>padA. </i>Moreover, it forms an operonic structure with <i>usp1,</i> a genewhose products display homology with proteins belonging to the UspA family of universal stress proteins. PadR is inactivated by the addition of <i>p-</i>coumaric, ferulic or caffeic acid to the culture medium. In order to better characterize the stress response of this bacterium to phenolic acids, we report here the kinetics and quantitative expression by qRT-PCR of the 3 genes from the <i>padA</i> locus. The expression of the 3 genes is very low in the non-induced condition, while the addition of 1.2 m<i>M</i><i>p</i>-coumaric acid induces an increase in the expression of <i>padA, padR </i>and<i> usp1 </i>by factors of 8,000, 37 and 13, respectively. These maximum relative transcript levels are obtained after 5 min of induction at the end of the exponential growth phase, while phenolic acid decarboxylase activity, not detectable before induction, is increased by a factor of 8,000 in 10 min. The apparent half-life of <i>padA</i> mRNA is about 1.4 min. The <i>padA-padR</i> system displays dynamic characteristics that are valuable to the development of tools for gene expression in this bacterium.